Automatic slack adjusters for maintaining a substantially constant clearance between a braking member and a rotatable braking surface to account for wear of either or both the braking member and the braking surface when the brake is in a released condition have been known for many years.
Brake assemblies of the type of particular interest herein generally feature a thrust member operative to move the braking member towards and away from the braking surface in response to corresponding application and release of the brake by an operator. Such brake assemblies are commonly used in vehicular brake applications where the braking member includes a frictional material that is urged against a rotating surface such as a disc surface for a disc type brake or a wheel drum surface in the case of a conventional brake. Wear of the frictional material results in increased clearance between the braking member and the braking surface resulting in greater movement of the thrust member being required in order to apply the brake. Adjustment of the position of the thrust member to account for such wear is commonly accomplished by an adjustment nut threadingly engaged with the thrust member that is caused to rotate upon application of the brake by an operator and enable the thrust member to advance the braking member towards the braking surface a distance sufficient to make up for any increase in clearance between the braking member and the braking surface arising from wear.
Automatic slack adjusters particularly adapted for vehicular brakes are respectively disclosed in U.S. Pat. Nos. 3,428,154; 4,085,830; 4,088,206; 4,094,390; 4,164,272; and Re. 26,965, the disclosures of all of which are included herein by reference. The problem common to all of such prior art slack adjusters, however, is their respective complex and costly designs resulting in a need to provide an effective automatic brake slack adjuster that is low cost, simple in design and that can be easily adjusted and maintained.